


An Angel and a Demon

by enkelimagnus



Category: Shadowhunters (TV)
Genre: Alternate Universe - Canon, Background Clary Fray/Jace Wayland, Background Magnus Bane/Alec Lightwood, Background Simon Lewis/Maia Roberts, F/M, Halloween, Halloween Costumes, Izzy is in an Angel costume and Sebastian in a Demon one
Language: English
Status: Completed
Published: 2019-11-01
Updated: 2019-11-01
Packaged: 2021-01-16 15:14:35
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,296
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21273275
Author URL: https://archiveofourown.org/users/enkelimagnus/pseuds/enkelimagnus
Summary: Sebastian has a hard time being comfortable with his true burnt appearance. Maybe a Halloween party with his girlfriend and their group of friends can help change that.





	An Angel and a Demon

**Author's Note:**

> Sebastian/Jonathan here is "portrayed by" Will Tudor. 
> 
> This is an AU-ish where he was never truly evil and turned himself in in early 2B.

“Are you sure your friends will be okay with this?” Sebastian asks. 

They are walking on the sidewalk, from the subway to the Hunter’s Moon. The hood of his hoodie is up and covering his face in shadows. He’s not wearing his usual “skin”. Isabelle has convinced him to use his burnt face as a Halloween costume. 

No matter what isabelle says, he can’t get himself to take off the hood yet. She keeps reassuring him, tells him no one will care, everyone will think it’s either a neat costume or he’s a poor guy who deserves a drink.

He doesn’t know HOW she’s convinced him to go like this. She didn’t force his hand, because she wouldn’t be able to. He just… agreed. And now he’s regretting it. His usual feeling of disgust when looking at himself is still there, and stronger than ever. 

“I am,” Isabelle shrugs, and she gently squeezes his hand. “Everything will be alright, Seb.” 

He sighs a little and nods. The Halloween party invitation had come rather late and neither of them had been able to do the research they’d wanted to do for it. In Isabelle’s purse, there was a cheap devil horns headband that he could put on with his red tshirt if he didn’t feel comfortable. In that case, he’d be a demon. It would also fit them. 

Isabelle was wearing a white lace bustier bra with a short white satin skirt tied over white booty shorts. Thigh-high white stockings with a less garter went up to her thigh with some very high silvery heeled sandals. She had put on fluffy wings and had a headband with a fluffy white halo over her head. She was an angel. And he was a demon. Fitting. 

She had one of his jackets on top of her outfit, because New York Fall was cold, and he didn’t want her to get sick, even if she was a strong angelic warrior. 

They made it to the Hunter’s Moon pretty quickly and before they walked in, Isabelle turned around and looked at him. He felt like moving away, keeping her from seeing his burnt face. He sighed a little as she took a step closer and slid her hands up his chest. 

“You don’t have to. You can go as a hot demon if you want to,” Isabelle whispers, impossibly close. He feels like he can see every speck of glitter in her eyeshadow. “Or we can go home.” 

“We made it here. We’re not coming home,” he replies and she nods. “I’ll… Listen, I will start with the demon. And we’ll see with the burn later okay?” 

Isabelle nods and takes the horns out of the pocket of the jacket. She gently pushes back his hood and when it falls, he’s put on the British blonde-haired face again. She arranges the headband into his hair and smiles. 

“Here you go, my sexy demon,” she grins and leans in to kiss him. He kisses her back, wrapping an arm around her waist under the too-big coat. “Let’s go?” She asks, and he nods. He keeps one of his arms around her as they walk in. 

The music is louder than it usually is. There are Downworlders drinking and enjoying themselves. Shadowhunters don’t really do Halloween, but the group Sebastian is now a part of is almost half Downworlders. 

Isabelle’s brother and his husband are wearing Addams Family costume, Alec as Gomez and Magnus as Morticia. Sebastian’s sister, Clary, is wearing a purple dress, purple boots and a lime green scarf, and Jace is wearing jeans and a white shirt with a blue color and a orange scarf tied around his neck. 

Simon Lewis, the vampire, and Maia Roberts, the werewolf, aren’t wearing any costume. Maia is working the bar and Simon has also invited his sister, a mundane girl called Rebecca. 

Clary stands up first as she sees them. She walks up to them and hugs Isabelle first, before turning to him. He waves hi awkwardly and she hugs him as well. The hug he gets a bit looser than the one Isabelle got, but it’s understandable.

Sebastian volunteers to get some drinks and says hi to Maia. He orders for everyone and gets his wallet out when someone walks up and stands next to him. It’s Rebecca. The dark-haired, obviously mundane in a cute way, woman smiles at him. 

“So. I’m Rebecca.”

“Sebastian,” he replies, and smiles back a little. 

“I know. Simon and Clary told me about you.” 

Sebastian immediately straightens up and licks his lips. He doesn’t like when people do that. Talk about him first without telling him. He can only guess the horrors Rebecca has heard about him. 

“I’m better now,” he says. 

Rebecca shrugs. “I was just told you might come with like… some cool burn costume.” 

Sebastian raises eyebrows and looks over at where Simon and Clary are standing. Next to them is Isabelle. She’s taken off the coat and she looks incredibly sexy. He clears his throat and looks away. 

“It’s… not a costume. I… that’s what I look like under the glamour,” Sebastian replies. 

“Oh.” 

“Yeah,” he has a bit of a chuckle. “Oh.” 

Rebecca is silent for a moment. Maia starts giving them their drinks. 

“And… I’m guessing you don’t like people seeing the burns, right?” 

Sebastian nods. “I… That and I don’t want people to be afraid and ask questions.” 

“You can always say that they are fake. Latex, FX makeup… you know. People can do some pretty realistic fake shit these days,” Rebecca says, taking her beer and sipping it a little. “They did tell me you used to be an asshole.” 

Sebastian chuckles more at that. “You can put it that way.” 

Rebecca shrugs. “Whatever it is… I think the burns thing would be hella cool. And you can still switch back if you’re uncomfy. I have the feeling the folks in here are pretty accepting about stuff one would find ugly.” 

She walks away on that, with her cute little vampire cape and the first of the rounds of drinks he’s paid for. He ends up going back to the table with the drinks. As he laughs and chats and drinks, Isabelle by his side, he keeps thinking back to the words he’s heard from Rebecca. 

At some point, he escapes to the bathroom. There, he stops in front of the mirror and stares at himself. He undoes the glamour, but only halfway. It’s still burnt, but it’s a bit less… ugly. And a bit less inhuman. And he finds that a good alternative. For now, he can start with that. 

He walks back out and there’s some silence as people stare. He feels bad. His skin kinda crawls and he’s thinking of turning the glamour back on entirely when he sees Isabelle’s wide eyes and the grin on her face. 

She rushes to him and wraps her arms around his neck. “I’m so proud of you, babe,” she grins and he finds himself smiling. He thinks she’s going to let go but she doesn’t. Not for a moment. She watches him, and leans up to kiss him. 

It’s just a peck, and Sebastian wonders how she’s doing that, because his face isn’t really kissable that way. Jace huffs something like ‘gross’ but she shoves her middle finger in his face. Sebastian spends the rest of the evening smiling. 

He turns the glamour back on as they leave the Hunter’s Moon. When they get home and stumble into bed, she’s still dressed as an angel and he’s still dressed as somewhat of a demon. They spend the rest of the night wrapped up in each other and he takes a lot of pleasure in ‘defiling’ his sexy angel.   
  


**Author's Note:**

> Hope you enjoyed this!
> 
> Shoot me an ask or a DM on my tumblr @enkelimagnus, or reach me on my Twitter @enkelimagnus!  
I have anons on and curiouscat so don't be shy!


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